Güyük, (born 1206, Mongolia—died 1248, Mongolia) grandson of Genghis Khan and eldest son and successor of Ögödei, the first khagan, or great khan, of the Mongols.

Güyük was elected to the throne in 1246, partly through the maneuvering of his mother. He was strongly influenced by Nestorianism, a form of Christianity considered a heresy by Western Christians, and he favoured Christian advisers. His election to the throne embittered the conqueror of Russia, Batu (d. c. 1255), also a grandson of Genghis. Güyük’s early death, however, prevented the dispute from tearing the Mongol Empire completely asunder.

...in Central Asia and Iran but was less able to control the always insubordinate Golden Horde. He died in 1241 and was succeeded, after a stormy regency under his widow, Töregene, by his son Güyük (Kuyug), who had already quarreled with his cousin Batu of the Golden Horde. Güyük died at Samarkand (now in Uzbekistan) in 1248, while preparing an attack on Batu.

On arriving at Sira Ordu, the Franciscans found that the interregnum that had followed the death of Ögödei, the supreme khan, or imperial ruler, had ended. His eldest son, Güyük (Kuyuk), had been designated to the throne; his formal election in a great kuriltai, or general assembly of shamans, was witnessed by the friars along with more than 3,000 envoys and deputies...